JPH02228310A - Encapsulation of preformed base material by graft copolymerization - Google Patents

Abstract

A process for encapsulating a preformed polymeric substrate comprises peroxidizing and hydroperoxidizing the surface of said preformed substrate using ozone and then carrying out a crosslinked graft copolymerization of selected ethylenically unsaturated monomers both on and surrounding (encapsulating) said substrate. Such encapsulation of substrates provides protective coatings, ablative coatings and, particularly, soft skirts for hard contact lenses.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for encapsulating preformed polymeric substrates by controlled graft copolymerization of selected ethylenically unsaturated monomers, and to products made by the process.

Graft polymerization itself has achieved considerable commercial success with A.
A number of graft copolymers such as BS (acrylonitrile/butadiene/styrene) have long been known in the art.

It is also known in the art that peroxy groups can be generated on the surface of a polymeric substrate by initial treatment with ionizing radiation or ozone in the presence of oxygen to graft polymerize various vinyl monomers. United States Patent Department 3,000
No. 8,920 and No. 3.070.573 disclose the grafting of selected monomers onto ozonated polymeric substrates.

Although such a method would, in theory, appear to be a universal method for modifying the properties of any polymeric substrate surface at will, U.S. Pat.
This is certainly not the case, as seen in the teachings of the '964 patents.

The purpose of such graft polymerization is to modify the polymeric substrate surface without causing significant changes in the physical properties of the substrate as a whole.

When implementing such a graft polymerization method, various problems arise. One important issue is that in carrying out the desired graft polymerization with vinyl monomers on a substrate,
The vinyl monomer simultaneously undergoes undesirable homopolymerization. To minimize this problem, graft polymerization in metal redox systems can be carried out using metal ions of various valences in a reduced state to convert the hydroxyl free radicals present into hydroxyl ions.
to minimize co-occurring homopolymerization problems (see U.S. Pat. No. 3.008.920, No. 4,311, 5
73 and 4.589.964).

U.S. Pat. No. 4,311,573 and 4.589.9
No. 64 teaches that other interlayers encountered in surface grafting of preformed polymeric substrates are for control of graft depth and density.

If the main properties of the substrate are preserved, the depth of grafting should not be increased beyond that necessary to modify the surface properties of the product; grafting at excessive depths or insufficient density to achieve the desired modification of properties; Swelling and degradation of the substrate material during grafting and processing are significant problems plaguing the aforementioned universal methods.

U.S. Pat. No. 4.311.573 and 4.589.9
Each specification of No. 64 discloses the use of variable valence metal ions (ferrous ions) and complexing agents (square It is described that graft polymerization is carried out using (acid) and the movement of the ions is controlled.

The present invention discloses the method of saturating the polymer substrate to be grafted with an insoluble liquid based on ethylenically unsaturated monomers and controlling the depth of graft polymerization on the substrate. No. 4,589.964, the method of the present invention does not require a complexing agent such as squaric acid.

One of the objects of the present invention is to provide an easy method of encapsulating and imparting desired properties to a preformed polymeric substrate.

Another object of the invention is to produce contact lenses with soft edges or other useful features by the method of the invention.

The present invention involves treating a preformed polymeric substrate with ozonation to produce peroxy and hydroperoxy groups on the substrate, and combining the peroxylated and hydroperoxylated substrate with an ethylenically unsaturated monomer or at least one crosslinker. Graft copolymerization with a monomer mixture containing monomers,
A method of encapsulating a preformed polymeric substrate comprising encapsulating the preformed polymeric substrate with a coating of a crosslinked polymer derived from said monomer or monomer blend.

In the initial stages of the process according to the invention, the polymeric substrate is saturated with a liquid in which the ethylenically unsaturated monomers are insoluble, either before or after carrying out the ozonation treatment which produces peroxy and hydroperoxy groups on the substrate. Or it can be swollen. This prevents the monomer from permeating into the substrate and limits the subsequent graft polymerization of the monomer to the surface of the substrate.

In another embodiment of the invention, the polymeric substrate is contacted with a chain transfer agent, preferably a primary or secondary C1-C4 alkanol or a solution containing it, to saturate or swell the polymer. The solution is insoluble in the perhalogenated liquid medium used in the subsequent ozonation step and confines the formation of peroxy and hydroperoxy groups to the surface of the polymer substrate.

In a preferred embodiment of the present invention, a hard polymer contact lens substrate is treated with ozone to generate peroxy and hydroperoxy groups on the substrate, the ozonated lens is placed in a mold, and the center of the lens is coated with the ozone. The periphery of the cured lens is treated with a hydrophilic vinyl monomer, preferably 2-hydroxyethyl methacrylate, and a crosslinking agent,
The mold is contacted with an aqueous grafting solution preferably containing a mixture of ethylene glycol dimethyl acrylate, and the mold is irradiated with ultraviolet light to decompose the peroxy and hydroperoxy groups present at the periphery of the ozonated lens in the grafting solution. Initiating graft cross-linking copolymerization with a vinyl monomer to generate a graft-crosslinked soft vinyl polymer rim at the peripheral edge of the hard contact lens;
A method of forming a soft polymer rim around the periphery of a hard polymer contact lens which improves eye comfort and wearability of the lens.

When ozone is applied to the substrate, peroxy groups (-0-0-) and hydroperoxy groups (-00H) are generated on the surface. Upon heat or other induced decomposition, the peroxy group cleaves into two active radicals attached to the polymer substrate surface, providing sites for the ethylenically unsaturated monomer to initiate graft polymerization.

On the other hand, upon heating or otherwise induced decomposition, the hydroperoxy group also cleaves into two active free radicals. One is bound to the polymer surface where it can initiate graft polymerization, while the other is a free hydroxyl group and is not bound to the surface.

The latter free radicals are used to initiate homopolymerization of the monomers, unless homopolymerization of the monomers is prevented or inhibited.

U.S. Patent Nos. 3.008.920 and 4.589.9
No. 64 discloses that effective homopolymerization inhibitors include cuprous ions, ferrous ions, or other metal ions of variable valence, such as cobalt, manganese, molybdenum, tin, indium, cerium, and chromium. , thallium and vanadium ions. A preferred metal salt that produces such metal ions is ferrous ammonia sulfate, as well as other ferrous salts such as ferrous sulfate, ferrous chloride, ferrous iodide and ferrous bromide. can be used as well.

These reduced valence salts, such as ferrous ammonium sulfate, react with hydroxyl free radicals in a redox system to form hydroxyl groups and oxidized salts, such as ferric ammonium sulfate. Minimizing or eliminating the concentration of hydroxyl free radicals in this manner effectively suppresses homopolymerization without initiating it.

The presence of homopolymer unbound to the substrate surface is undesirable, producing highly extractable and unstable surface properties, so when only surface modification is desired, the graft polymerization process of the invention Polymerization inhibitors are usually added.

However, in the present invention, the cross-linked homopolymerization is the key point of the present invention, and the method of the present invention provides a method of encapsulation of the substrate by homopolymer encapsulation. In a variant of the invention, the ethylenically unsaturated monomer can initiate a reaction in the presence of ions, both by active free radicals bound to the substrate surface and by active hydroxyl radicals present in the system. A completely hydrogel network polymer with no or little homopolymerization inhibitor present is covalently bonded into a three-dimensional structure by the presence of a crosslinking agent.

Encapsulation of the material with a protective coating that can be removed by weathering or other management regimes such as leaving it in the soil for a period of time is a benefit of the product made by this variant of the invention, since it has zero seeds. A protective coating is contemplated.

It is known that the use of metal ions of variable valence, such as ferrous and cuprous ions, can suppress homopolymerization during graft polymerization of substrates containing hydroperoxy groups.

However, ferrous ions inhibit homopolymerization;
Its use is limited because the ions penetrate into the polymer substrate and cause certain graft polymerizations to occur in undesired locations, ie, inside the substrate.

The effect of graft polymerization at unfavorable locations is distortion of the substrate, resulting in a simultaneous loss of physical and dimensional stability and original properties. Such distortion is generally undesirable and unacceptable in the contact lens field for obvious reasons.

Another aspect of the invention is a technique to devise a soft polymer edge around the periphery of a hard polymer contact lens. Current techniques for manufacturing such modified lenses are complex, labor intensive, and impossibly wasteful.

However, the method of the present invention provides a facile means for the production of such modified lenses. Ozone treatment of a hard polymer lens substrate generates peroxy groups and hydroperoxy groups on the substrate, the ozonated lens is placed in a mold, the center of the lens is coated, and the peripheral edge of the ozonated lens is coated with wood-philic material. Immersion in an aqueous grafting solution containing monomers and a crosslinking agent, the grafting solution containing a suitable mixture of woodophilic monomers and crosslinking monomers, imparts the desired properties needed to the soft polymeric rim of the contact lens and to the rigid contact lens. This provides rigid contact lenses with greatly improved ocular comfort and other ancillary advantages not normally found in lenses.

The filled malt containing the appropriate grafting monomer is irradiated with ultraviolet light. This irradiation decomposes the peroxy and hydroperoxy groups present at the periphery of the ozonated lens and initiates the grafting and cross-linking copolymerization of the monomer mixture within the mold, thereby creating the desired structure that is firmly bonded to the rigid contact lens by grafting. Forms a soft polymer rim of the same nature.

Preformed polymeric substrates that can be used in the method of the invention include shaped polymeric products such as films, fibers,
Either a thin film, a device or a contact lens containing product that requires encapsulation or coating.

The only requirement is a polymer to make the molded product.

As such, when acted upon by ozone, it has hydrocarbon groups somewhere in its structure that are amenable to peroxidation and hydroperoxidation, producing peroxy and hydroperoxy groups on the surface of the preformed polymer substrate. It is something.

Polymeric materials useful in the present invention include polyolefins, polyesters, polyamides, cellulosic polymers, polyurethanes, non-silicone hydrogels, hydrophilic polysiloxanes, hydrophobic polysiloxanes, poly(
Polymers containing (alkylene oxide) units, polycarbonates, silicone rubbers, natural and synthetic rubbers, epoxy resins, polyvinyl chlorides, polystyrenes, poly(methyl methacrylate)s and copolymers.

Peroxy and hydroperoxy groups are conveniently introduced onto the surface of a preformed polymeric substrate by applying ozone (0,) to the substrate. This is carried out by suitably suspending, positioning or otherwise securing the preformed substrate in a room or container, and the surface to be modified is exposed to a gas carrier, such as ozonated air, ozonated oxygen, or Good contact with ozone dissolved in a perhalogenated solvent is carried out for a sufficient time to absorb the required ozone onto the polymer surface and form the desired peroxy and hydroperoxy groups. Generally, this takes less than an hour, usually about 30 minutes.

The reaction temperature is generally not limited, but the reaction temperature is 0.
The temperature range is from 100°C to 100°C.

For convenience, room temperature is preferred.

In order to facilitate the reaction between the polymeric substrate and ozone to form the hydroperoxidized substrate, the reaction is preferably carried out in the presence of a small amount of moisture; indeed, in the case of hydrogel materials, ozone treatment The polymeric substrate can be saturated with water before doing so.

Ozone is typically created by bubbling an oxygen-containing gas, such as air or pure oxygen, through a standard ozone generator and mixing it with a carrier gas.

When air is used, approximately 2% by weight ozone is typically produced. When pure oxygen is used, approximately 4% by weight of ozone is produced.

Ozone produced by an ozone generator also contains carbon tetrachloride,
1,1.2-trichloro-1,2,2-trifluoroethane, octafluorocyclobutane, perfluorohexane, perfluorohebbutane, perfluoro(1,3-
dimethylcyclohexane), perfluorocyclohexane, 1,1.1-trichloro-2,2,2-trifluoroethane, l,j,1°2-tetrachloro-2,2-difluoroethane and 1.1,2.2- Tetrachloro
It can be dissolved in perhalogenated solvents such as 1,2-difluoroethane. Preferably, carbon tetrachloride, perfluoro-(1,3-dimethylcyclohexane), l,
1,2-Trichloro-1,2,2-trifluoroethane or perfluorohexane are preferred perhalogenated solvents.

Other embodiments of the invention provide that the preformed polymeric substrate is first saturated or saturated with a chain transfer agent or a solution containing the same before carrying out the ozonation using ozone dissolved in a perhalogenated solvent. It is to swell. The solution containing the chain transfer agent is insoluble in the liquid medium containing ozone.

Perhalogenated solvents are the solvents mentioned above, especially perfluoro(
1,3-dimethylcyclohexane).

The chain transfer agent is preferably a C1-C4 primary or secondary alkanol, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, 5ee-butyl alcohol or isobutyl alcohol. The solution containing the chain transfer agent can also contain water or a tertiary lower alkanol, such as tert-butyl alcohol, to aid solubility of the chain transfer agent.

Other compounds such as mercaptans are also effective chain transfer agents, but mercaptans are used for sensory reasons (odor).
Therefore, it is excluded from consideration of wooden purposes.

Isopropanol is a particularly preferred chain transfer agent in the process of the invention.

When the substrate is a hydrogel, there are two advantages from the above embodiments of the invention.

These are: Firstly, the ozonation is done on the polymer substrate in a swollen or expanded state. The subsequent graft copolymerization is performed on the substrate already in its normal physical state and size, and the end-use product, i.e., biomedical device, contact lens, etc., is free from structural and morphological changes that may occur during use. Minimize the chances.

Second, primary or secondary alcohols act as chain transfer agents. The presence of such compounds within the swollen polymeric substrate helps to prevent graft polymerization from occurring within the polymeric substrate later in the process of the invention by confining peroxylation and hydroperoxylation to the surface of the substrate. Become.

Another aspect of the invention is the ozonation of polysiloxane polymer substrates, especially contact lenses, in the presence of perhalogenated hydrocarbon liquids, especially 1,1,2-trichloro-1,2,2-trifluoroethane. be. Polysiloxane contact lenses exhibit high surface tackiness that causes them to stick together when ozonated in gaseous or aqueous media and causes irreparable damage to the lenses when separated.

Polysiloxanes swell in perhalogenated hydrocarbon liquids, and the high solubility of ozone in these liquids reduces the peroxy and hydroperoxy group sites on the polysiloxane lens surface compared to ozone treatment in water. It increases significantly (up to 13 times) and is favorable for the subsequent graft polymerization.

The preformed polymeric substrate is contacted with ozone in a gas or liquid phase medium and air-dried at room temperature to remove residual ozone from the ozonated substrate. Since ozonation occurs primarily at the site of contact with ozone, peroxylated groups and hydroperoxylated groups may be present in unspecified interiors or recesses into which ozone has entered.

Ozonated substrates have peroxy and hydroperoxy groups that are unstable when heated, but ozonated substrates have low 1! (O to 20
℃) for long periods of time (several months) without loss of peroxy and hydroperoxy groups.

Subsequent graft polymerization of modified monomers anywhere on the preformed polymeric substrate except at the surface in order to prevent undesirable changes in the overall properties of the polymer, including the fundamental native properties of the substrate itself. Preferably, grafting is prevented or at least minimized.

To prevent the grafting monomer from penetrating to a significant depth within the polymer substrate, the ozonated substrate is air-dried to remove residual ozone and then treated in various ways prior to carrying out the graft polymerization.

In either case, the ozone-treated substrate is purged with nitrogen gas, so that the subsequent graft polymerization is not hindered.

Penetration into the ozonated substrate depends on the nature of the substrate and vinyl monomer used in the graft polymerization, e.g.
Air-dried, nitrogen-purged, and ozonated substrates can be used directly in the graft polymerization process if molecular weight, polarity, etc., do not appear to be a problem, and there is no possibility of excessive penetration into the substrate by the grafting monomer. There's no need to worry.

If such penetration of vinyl graft monomers may be a problem, the air-dried and ozonated substrate is purged with nitrogen and the interstices and recesses inside the substrate are then saturated with liquid. This liquid is chosen so that it does not essentially dissolve the graft monomer system. The grafting monomer is thus virtually excluded from grafting at any substrate site other than the surface. This is an easy way to limit grafting to the precise location on the substrate surface that is to be modified without changing the overall physical properties of the substrate.

Depending on the solubility of the grafting monomer system used, the saturated liquid is water, organic hydrocarbons, perhalogenated hydrocarbons or liquid mixtures.

Organic hydrocarbon liquids useful for saturating ozonated substrates are inert to vinyl polymerization and include aliphatic, cycloaliphatic and aromatic hydrocarbons such as hexane, heptane, cyclohexane, toluene and It's xylene.

Perhalogenated hydrocarbons useful for saturating ozonated substrates include carbon tetrachloride, 1°1,2-trichloro-1,2,2-trifluoroethane, octafluorocyclobutane, perfluorohexane, among others. , perfluorohebutane, perfluorocyclohexane, 1,1.1
Trichloro-2,2,2-trifluoroethane, perfluoro-(1,3-dimethylcyclohexane), 1,1
, 1,2-tetrachloro-2,2-difluoroethane and 1,1,2.2-tetrachloro-1,2-difluoroethane.

Generally, relatively small amounts (by weight) of monomer are actually used for grafting onto the polymeric substrate surface to effect the desired modification of the properties of the substrate surface.

Graft polymerization is generally carried out using an aqueous solution of an ethylenically unsaturated monomer or a mixture of monomers capable of graft addition polymerization onto the substrate surface.

If the monomer does not have some degree of solubility in water, a co-solvent, preferably tert-butyl alcohol, is used to increase the solubility of the monomer in the aqueous graft polymerization system.

If desired, the graft polymerization mixture can contain catalytic amounts of conventional catalysts typically used in the polymerization of vinyl compounds, preferably free radical catalysts. Catalysts of particular interest are conventional peroxide and azo catalysts, such as hydrogen peroxide,
Ozonated substrates, often with peroxy and hydroperoxy groups, benzoyl peroxide, tert-butyl peroctoate or azobis(isobutyronitrile), are themselves active and act as initiators. The addition of is not necessary.

Furthermore, if necessary, the graft polymerization can be carried out by actinic radiation in the presence or absence of a photoinitiator.

The choice of monomer or monomers depends on the nature of the substrate and the specific surface modification desired. Thus, the monomers can be hydrophilic, hydrophobic, cross-linking, stainable, bactericidal, or have any of a wide range of properties necessary to achieve the desired modification.

Suitable water-permeable monomers are generally water-soluble conventional vinyl monomers, for example of the general formula R H, C=C-COOR.

acrylic esters and methacrylic esters (wherein R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom or a carboxy group, a hydroxy group, an amino group, a lower alkylamino group, a lower dialkylamino group, 2 to about 1
Substituted with one or more water-soluble groups such as polyethylene oxide groups consisting of 00 repeating units, or - or more sulfate, phosphate, sulfonate, phosphonate, carboxamide, sulfonamide or phosphonamide groups. represents an aliphatic hydrocarbon group having up to about 10 carbon atoms) or mixtures thereof: formula, H* C= CCON HR! Acrylamide and methacrylamide (wherein R3 and R2 have the same meanings as above); formula, H*C=, CCON (R
3) z acrylamide and methacrylamide (wherein R3 is lower alkyl having 1 to 3 carbon atoms, R1
have the same meaning as above); maleic acid esters and fumaric acid esters of the formula, Rz OOCCH= CHCOORz (wherein, R2 is
(same meaning as above); formula, HtC=C, HOR.

Vinyl ether of the formula (wherein R2 has the same meaning as above); Aliphatic vinyl compound of the formula, R,CH=CHRt (wherein R1 has the same meaning as above, and R8 has the same meaning as above) (excluding hydrogen atoms):
and vinyl-substituted heterocyclic compounds such as vinylpyridines, piperidines, and imidazoles, and N-vinyllactams such as N-vinyl-2-pyrrolidone.

Examples of useful water-soluble monomers (not all of which are included in the general formula above) include =2-hydroxyethyl-12- and 3-hydroxypropyl-12,3-dihydroxypropyl-, polyethoxyethyl - and polyethoxypropyl - acrylic esters, methacrylic esters, acrylamides and methacrylamides; acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N, N-
Dimethylacrylamide, N,N-dimethylmethacrylamide; each N of acrylic acid and methacrylic acid.

N-dimethyl- and N,N-diethyl-aminoethyl esters and the corresponding acrylamides and methacrylamides; 2- and 4-vinylpyridine; 4- and 2-
Methyl-5-vinylpyridine; N-methyl-4-vinylpiperidine; 2-methyl-1-vinylimidazole: N,N-dimethylarylamine; dimethylaminoethyl vinyl ether; N-vinylpyrrolidone;
Acrylic acid and methacrylic acid; lower hydroxyalkyl mono- and diesters of fumaric acid and maleic acid, such as itaconic acid, crotonic acid, fumaric acid and maleic acid, and 2-hydroxyethyl esters of fumaric acid and maleic acid, acrylic acid and methacrylic acid. Examples include sodium salts of acids; anofomaleic acid; 2-methacryloyloxyethylsulfonic acid and arylsulfonic acid.

Preferred water-soluble monomers are 2-hydroxyethyl methacrylate, N,N-dimethylacrylamide, acrylic acid and methacrylic acid, most preferably 2-hydroxyethyl methacrylate.

Suitable hydrophobic copolymerizable monomers are conventional vinyl monomers which are insoluble in water, examples being acrylic and methacrylic esters of the general formula R H2C=C-COOR4 , where R is , and R4 is unsubstituted or one or more alkoxy groups, alkanoyloxy groups, or alkyl groups having 12 or less carbon atoms.

or a linear or branched aliphatic group having up to 20 carbon atoms substituted with a halogen, particularly a chlorine atom or preferably a fluorine atom, or a polyalkyleneoxy group having 3 to 5 carbon atoms and consisting of 2 to about 100 units. , representing an alicyclic group or an aromatic group), R4 H, C=C-C0NHR.

Acrylamide and methacrylamide (wherein R1 and R4 have the same meanings as above); formula, H2C=CH
-0-R4 vinyl ether (wherein R1 has the same meaning as above); formula, H,C=CH-0CO-R.

Vinyl ester (wherein R4 has the same meaning as above): Formula, R,0OC-HC=CH-COOR.

Maleic esters and fumaric esters (in the formula,
R4 has the same meaning as above); and the formula, R+ CH
= CHR4 vinyl-substituted hydrocarbon (wherein R1 and R4 have the same meanings as above).

Useful hydrophobic monomers are not all represented by the general formula above, but include, for example: methyl, ethyl, propyl, isopropyl, butyl, ethoxyethyl, methoxyethyl, ethoxypropyl, phenyl, benzyl, cyclohexyl. , hexafluoroisopropyl or n-octyl-acrylic esters and -methacrylic esters, and the corresponding acrylamides and methacrylamides; fumaric acid dimethyl ester,
Dimethyl maleate, diethyl fumarate, methyl vinyl ether, ethoxyethyl vinyl ether, vinyl acetate, vinyl propionate, vinyl benzoate, acrylonitrile, styrene, α-methylstyrene, l-hexene, vinyl chloride, vinyl methyl ketone, stearin acid vinyl ester, 2-hexene and methacrylic acid 2-ethylhexyl ester.

Suitable crosslinking agents are diolefin-containing monomers, such as aryl esters of diacrylic acid and methacrylic acid; diacrylates and dimethacrylates of alkylene glycols and polyalkylene glycols, such as ethylene glycol dimethacrylate and propylene glycol dimethyl acrylate. ; trimethylolpropane triacrylate; pentaerythritol tetraacrylate, divinylbenzene; divinyl ether; divinyl sulfone; bisphenol A diacrylate or methacrylate; methylene bisacrylamide; diarylphthalate; triarylmelamine; and diacrylate of hexamethylene and dimethacrylate.

EXAMPLES The following examples are included for illustrative purposes only and are not intended to limit the nature or scope of the invention in any way.

To determine the relative ozonation rate of a polysiloxane film in water compared to that in perhalogenated hydrocarbons, separate samples of the same polysiloxane film were tested in water and in 1,1,2-trichloro- Ozone placed in 1,2,2-trifluoroethane (Freon TF or 113) and produced by a conventional ozone generator was
It was vented for 0 minutes. Ozone solubility in water is 4.5 ppm,
That for Freon TF or 113 was 491 ppm.

Multiple polysiloxane films in the same aqueous system aggregated very quickly. Analysis of the hydroperoxide content of the film (iodometric titration method) revealed that the hydroperoxide content was 0.924 .mu./g or 0.09%.

Samples of ozonated polysiloxane films in the Freon TF or 113 system were separated from each other, and the hydroperoxide content of the films was 12
It was 11g/g or 1.2%.

If the ozone treatment of the base material is carried out with a Freon system,
The hydroperoxide content of the substrate material after ozonation is clearly high.

According to Example 1, various halogen-containing carbon compounds, such as carbon tetrachloride, l.

1. Various types showing increased hydroperoxide formation on the film surface due to the swelling effect of silicone macromer films in 21-dichloro-1,2,2-trifluoroethane (Freon 113) and perfluoro(l,3-dimethylcyclohexane). A test was conducted.

A first sample of film was placed in a beaker containing carbon tetrachloride, a second sample of film was placed in a beaker of Freon 113,
Another film sample was placed in a beaker of perfluoro-(1,3-dimethylcyclohexane). After each film was equilibrated, ozonation was carried out for 5 minutes. After air-drying the film for 45 minutes, it was soaked in deionized water for 10 minutes in a nitrogen stream.
0g, N.

N-dimethylacrylamide 1. 0.14 g of methylenebisacrylamide and 0.3 g of ammonium sulfate ferrous hexahydrate. After 8 minutes, the film was removed from the grafting solution.

The film was distorted, opaque and very smooth due to deep and strong penetration of the graft.

Under the above conditions, the polysiloxane film treated with ozone in water and grafted for 5 minutes was at the limit of becoming smooth. The films were not as highly hydroperoxidized as films ozonated in halogenated carbon compounds, so they were not highly grafted or distorted.

Polysiloxane contact lenses were prepared using 1,1,2-trichloro-1,2,2-trifluoroethane (Freon T).
The ozonated lenses were then air-dried and returned to Freon 113 to swell.

The lens swollen with Freon 113 was soaked in 50 g of water and TE.
1 g N,N-dimethylacrylamide dissolved in 50 g rt-butyl alcohol, 0.14 g ethylene glycol dimethyl acrylate, 1 ferrous ammonium sulfate 6
The hydrate was placed in a grafting monomer solution of 0.1 g.

Graft polymerization was carried out for 30 minutes at room temperature in a nitrogen stream.

The grafted lenses were removed from the monomer solution, extracted with water and hydrated with deionized water for general human eye acceptability testing.

After 15 minutes on the eye, the grafted siloxane lenses were clear and hydrated, with no protein or lipid deposits visible.

The ungrafted polysiloxane control lens completely lost moisture and became opaque after 1 minute of contact with the eye.

Example 4: Similar to Example 3, polysiloxane contact lenses were ozonated and then swollen in Freon 113. The ozonated and swollen lenses were placed individually in the selected grafting solution as described in Example 3, except that each stack of hydrophobic methyl methacrylate monomers was added to the solution.

The contact angle was measured on the grafted lenses and the influence of methyl methacrylate content on the hydrophobicity of the grafted lenses was investigated.

0.1 320.2
320.4
3 40.8
441.0 44
Ungrafted Lenses 80 Apparently, increasing the hydrophobicity of the grafted polymer on the polysiloxane lens surface significantly increased the contact angle and hydrophobicity of the lens.

Example 5 A silicone macromer film was ozonated in water for 5 minutes at room temperature, air dried for 30 minutes, and then placed in a beaker containing deionized water for 15 minutes in a nitrogen stream.The film was then incubated with 100 g of deionized water.

N,N-dimethylacrylamide 1. 0.14 g of methylenebisacrylamide and 0.3 g of ammonium sulfate ferrous hexahydrate. The films were held in the grafting solution for 15 minutes under a nitrogen stream and then removed and evaluated. Although the film was very smooth, it was opaque and distorted due to deep penetration of the graft material into the base film.

Example 6 In this example, in order to limit the grafting to the sample surface, a polysiloxane contact lens was placed in water at room temperature for 65 minutes, demonstrating the effect of pre-applying the substrate with a halogenated carbon compound or hydrocarbon. Ozonated with
Next, after air drying the lens for 30 minutes, carbon tetrachloride, hexane, 1.1.2-trichloro-L, 2.2-trifluoroethane (Freon 113) or perfluoro-(1,3-dimethylcyclohexane) was added. placed in a beaker. Each beaker was evaporated by blowing nitrogen gas and immersed in the liquid for 15 minutes.

The swollen lens was then soaked in deionized water 1008%N,
N-dimethylacrylamide t,og was placed in a grafting solution consisting of 0.14 g of methylenebisacrylamide and 0.3 g of ammonium sulfate ferrous hexate.

Grafting was carried out for 15 minutes in a nitrogen stream.

The grafted lenses were found to be transparent, smooth, and undistorted because the grafting of the hydrophilic polymer was confined to the siloxane contact lens surface.

This was in contrast to the grafted film made in Example 5, which was opaque and distorted due to graft penetration.

Example 7: Properties of Contact Lenses The surface of a polysiloxane contact lens was treated with ozone in the air for 1 minute.

After air drying the lens, 1,1,2-trichloro-1,2,2
In trifluoroethane (Freon TF or 113),
The lens was saturated and swollen.

Next, in a nitrogen stream, 1 g of N,N-dimethylacrylamide, 0.14 g of methylenebisacrylamide and ferrous ammonium sulfate hexahydrate were dissolved in 100 g of water.
The lens was placed in a solution consisting of 0.3 g. Graft polymerization was carried out for 15 minutes at room temperature.

The lenses were then extracted with water. The properties of the grafted lenses and non-grafted control lenses are shown in the table below.

1L2L Yujin Thickness of grafted lens (μ) 104 102 Oxygen flow rate” 0.65 0.86 Oxygen permeability” 76.8 72.8 Contact angle Advance 94 25 Retraction 51 25 1μQ Ot / (!l[ Oxygen flow rate in win 8
"Oxygen permeability: 0, -D k = a + t (S T P) X C111
/(!I!
3-dimethylcyclohexane) and treated with ozone for 5 minutes. After 30 minutes of air-drying, the film was placed in a beaker containing deionized water for 15 minutes under a nitrogen stream and treated with 100 g of deionized water, 1N of N-dimethylacrylamide, and 1. Og, methylenebisacrylamide 0.
14 g and ammonium sulfate ferrous hexahydrate 0.3 g
into a grafting solution consisting of:

After grafting for 15 minutes under a nitrogen stream, the film was removed and evaluated. Because of the chain transfer properties of the aqueous isopropanol system, grafting was confined to the substrate surface, and the grafted films were transparent, smooth, and undistorted.

It is opaque and distorted due to graft penetration,
In contrast to the grafted film made in Example 5.

Example 9 A study demonstrating the effect of chain transfer agents on grafting was performed in the general manner described in Example 8.

However, the time for soaking the equilibrated silicone macromer film in water was shortened from 5 seconds to 3 seconds.

The film after the end of the grafting step was not as smooth as the film obtained in Example 8.

It is clear that the amount of chain transfer agent (in this case isopropanol) present in the substrate film at equilibrium determines the amount of grafting that subsequently takes place. In this example, a large amount of isopropanol was present, resulting in a small amount of grafting.

Example 10 Effect of the amount of chain transfer agent present on subsequent grafting
It was also demonstrated that the method described in Example 8 was repeated exactly, except that a 0% aqueous isopropanol (50 g water and 50 g isopropanol) concentration was used.

After the end of the grafting step, the film was not as smooth as the film obtained by the method of Example 8, and the increase in the amount of chain transfer agent (in this case isopropanol) present in the equilibrated substrate was due to the subsequent grafting. It was shown that the amount of produced was reduced.

Example 11 A silicone macromer film was prepared using a 10% isopropanol aqueous solution (90 g of water and 10 g of isopropyl alcohol).
) and treated with ozone for 5 minutes at room temperature. Air dry 15
After 1 minute, the film was placed in a beaker containing water and bubbled with nitrogen for 15 minutes.

Then 100g% N,N-dimethylacrylamide in deionized water 1. Og, methylenebisacrylamide 0.
14 g and ammonium sulfate ferrous hexahydrate 0.3 g
The grafting solution was placed in the grafting solution for 30 minutes.

After this time, the removed film was clear and totally free of grafting, unlike the very smooth, opaque, distorted grafted film obtained in Example 5.

The only difference in the methods of Example 5 and Example 11 is that
The presence of excess chain transfer agent (isopropanol) in this example prevents grafting from occurring.

Example 12 A polysiloxane-polyurethane film was equilibrated in isopropyl alcohol and ozonated in perfluoro(1,3-dimethylcyclohexane) for 10 minutes at room temperature.

Control films that were or were not initially equilibrated with isopropanol were also treated with perfluorinated (1,
3-dimethylcyclohexane).

Each ozonated film was then placed in a beaker containing water. Films equilibrated with isopropanol were clear, while control films that were not equilibrated with isopropanol became very opaque.

Polar hydroperoxide groups formed in the ozonated control film, which absorbed water and became opaque.

For films that were first equilibrated with isopropanol and then treated with ozonation, the chain transfer agent (isopropanol)
However, in the ozonation process, hydrogen atoms are transferred to the free radicals generated on the film, thereby preventing the formation of hydroperoxy groups.Therefore, there are no hydroperoxy groups, so the film is free from hydroperoxy groups. protected and the transparency of the film is maintained.

Example 13 Polysiloxane film 1.1.2-1 Lichrolow 1
．． 2.2-Trifluoroethane (Freon 113 or T
F) The film surface was treated with ozone by placing it in a wafer and exposing it to ozone for 15 minutes at room temperature.Then, the film was taken out and air-dried for 25 minutes. It was further placed in water and continuously purged with nitrogen for 15 minutes.

The ozonated film was immersed in a grafting solution consisting of 100 g of water, i,o g of N,N-dimethylacrylamide, 0.14 g of methylene bisacrylamide, and 0.3 g of Me ammonium ferrous hexahydrate. Nitrogen purging was continued during the 30 minute grafting period.

The film was then removed from the grafting solution and washed with water. A dense graft was formed on the film surface. This is evidenced by a smooth, non-swelling grafted substrate product.

Example 14 According to Example 13, a second siloxane film was treated with ozone and grafted. However, in this case,
The concentration of ammonium ferrous sulfate hexahydrate in the grafting solution was reduced from 0.3 g to 0.1 g.

In this case, the grafted and water-washed polysiloxane film was completely encapsulated with a hydrogel envelope. The thickness of this envelope was several millimeters in the hydrated state.

The hydrogel capsules are insoluble, indicating that they are highly cross-linked. This hydrogel had a high water content, and dehydration-rehydration tests showed that water utilization and dehydration were reversible in the hydrogel.

Examples 13 and 14 demonstrate the effect of ferrous ion concentration on the ability of a grafting solution to produce hydrogel capsules around a particular substrate.

By controlling the ferrous ion concentration, hydroperoxy compounds can be decomposed into alkoxy and hydroxyl radicals. When the ferrous ion concentration decreases, the hydroxyl free radicals, without being converted to hydroxyl ions, initiate polymer growth within the grafting solution and crosslink into the grafted polymer at the substrate surface. The result is a crosslinked hydrogel capsule around the substrate, which is then bound to the substrate.

Example 15: Several types of hard polysiloxane contact lenses were prepared using 1.1.2-trichloro-1,2,2-trifluoroethane (Freon TF).
or 113) and treated with ozone at room temperature for 15 minutes to generate peroxy and hydroperoxy groups on the lens surface.6Then, the lens was air-dried, exposed to a nitrogen stream, and treated with ozone at room temperature.
Hydrate with deionized water for 45 minutes.

The lenses were then placed in a mold, with the center of each lens coated and the periphery of each lens left uncoated. 5.5% by weight of ethylene glycol dimethyl acrylate crosslinker
A 2-hydroxyethyl methacrylate solution containing 2-hydroxyethyl methacrylate was purged with nitrogen and brought into contact with the periphery of a contact lens placed in a mold under a nitrogen stream. Thereafter, this site was irradiated with ultraviolet rays for 3 hours to cause grafting and copolymerization.

Each lens was observed to have a unique soft polymer rim that bonded tightly to it and remained intact.

Claims (1)

Claims: 1. A preformed polymer substrate is treated with ozone to generate peroxy and hydroperoxy groups on the substrate, and the peroxylated and hydroperoxylated substrate is treated with an ethylenically unsaturated monomer or Graft copolymerizing with a monomer mixture comprising at least one crosslinking monomer, coating the preformed polymer substrate with a crosslinked polymer derived from the monomer or monomer mixture to encapsulate the preformed polymer substrate, and subjecting the preformed polymer substrate to an ozonation step. A process for the encapsulation of preformed polymeric substrates, characterized in that before or after the substrate is saturated or swollen with a liquid in which the ethylenically unsaturated monomer or monomer mixture is not dissolved. 2. The graft copolymerization process according to claim 1, wherein the step of graft copolymerization is carried out in the absence or in the presence of a very low concentration of variable valence metal ions to promote homopolymerization during grafting of ethylenically unsaturated monomers or monomer mixtures. Method. 3. The method according to claim 2, wherein the metal ion is a ferrous ion. 4. A method according to claim 1, wherein the ozonation is carried out in a medium of water, air, oxygen or perhalogenated hydrocarbons. 5. A method according to claim 4, wherein the ozonation is carried out in a perhalogenated hydrocarbon medium. 6 The perhalogenated hydrocarbon medium is carbon tetrachloride, 1,
1,2-trichloro-1,2,2-trifluoroethane, perfluorohexane or perfluoro-(1,3-
5. The method according to claim 4, wherein the compound is dimethylcyclohexane). 7 The perhalogenated hydrocarbon medium is perfluoro-(1
, 3-dimethylcyclohexane). 8 Ozone treatment of a hard polymer contact lens substrate to generate peroxy groups and hydroperoxy groups on the substrate, and mold (mol) of the ozonated lens.
d), coating the center of the lens and contacting the peripheral edge of the ozonated lens with an aqueous grafting solution containing a mixture of a hydrophilic vinyl monomer and a vinyl crosslinker;
The mold is irradiated with ultraviolet light to decompose the peroxy and hydroperoxy groups present at the periphery of the ozonated lens and initiate graft cross-linking copolymerization with the vinyl monomer in the grafting solution. 2. The method of claim 1, comprising forming a graft-crosslinked soft vinyl polymer edge to enhance the eye comfort and wearability of the lens. 9. The method of claim 8, wherein the hydrophilic vinyl monomer is 2-hydroxyethyl methacrylate and the vinyl crosslinker is ethylene glycol dimethacrylate. 10. An encapsulated product made by the method of claim 1. 11. A hard polymer contact lens made by the method of claim 8 and having a soft vinyl polymer rim bonded to the lens. 12 contacting the polymeric substrate with a chain transfer agent or a solution containing the same to saturate or swell the polymer, such that the solution is insoluble in the perhalogenated liquid medium subsequently used during the ozonation step; confining the hydroperoxylation and peroxylation carried out to the polymer surface and ozonating the saturated or swollen polymer with ozone dissolved in a perhalogenated liquid medium insoluble in the solution containing the chain transfer agent;
The peroxylated and hydroperoxylated substrate is graft copolymerized with an ethylenically unsaturated monomer or a monomer mixture comprising at least one crosslinking monomer, and then preformed by coating with a crosslinked polymer derived from the monomer or monomer mixture. A method for encapsulating a preformed polymer substrate comprising encapsulating a preformed polymer substrate. 13. The method of claim 12, wherein the copolymerization step is carried out in the absence or only in the presence of low concentrations of variable valence metal ions to promote homopolymerization upon grafting of the ethylenically unsaturated monomer or monomer mixture. . 14. The method according to claim 12, wherein the metal ion is a ferrous ion. 15. The method according to claim 12, wherein the chain transfer agent is a primary or secondary alkanol having 1 to 4 carbon atoms. 16. The method according to claim 15, wherein the chain transfer agent is dissolved in water or an aqueous solution containing tert-butyl alcohol. 17 Claim 1 wherein the chain transfer agent is isopropanol
5. The method described in 5. 18 The perhalogenated liquid medium is carbon tetrachloride, 1,1
, 2-trichloro-1,2,2-trifluoroethane,
13. The method according to claim 12, which is perfluorohexane or perfluoro-(1,3-dimethylcyclohexane). 19 The perhalogenated liquid medium is perfluoro(1,
19. The method according to claim 18, wherein the cyclohexane is 3-dimethylcyclohexane. 20 A hard polymer contact lens substrate is ozonated to generate peroxy groups and hydroperoxy groups on the substrate, the ozonated lens is placed in a mold, the center of the lens is coated, and the periphery of the ozonated lens is coated. The mold is brought into contact with a grafting aqueous solution containing a mixture of a hydrophilic vinyl monomer and a vinyl crosslinking agent, and the mold is irradiated with ultraviolet light to decompose the peroxy groups and hydroperoxy groups present at the periphery of the ozone-treated lens, resulting in grafting. Initiating graft crosslinking copolymerization with a vinyl monomer in solution to produce a graft copolymerized and crosslinked soft vinyl polymer rim around the periphery of a rigid contact lens to improve eye comfort and wearability of the lens. 13. The method of claim 12 for producing a peripheral soft polymer rim of a hard polymer contact lens comprising: 21. The method of claim 20, wherein the hydrophilic vinyl monomer is 2-hydroxyethyl methacrylate and the vinyl crosslinker is ethylene glycol dimethyl acrylate. 22. An encapsulated product made by the method of claim 12. 23. A hard polymer contact lens made by the method of claim 20 and having a soft vinyl polymer rim bonded to the lens.